Feeling Hot Hot Hot.

[Baxter]

Now then.
What would cause a AAZ to run really hot under load?
Customers Van that I have put a AAZ into, the van was a 1.6TD from stock.
Took on long test drive once done, took it up a reasonably long drag and it got kinda hot, there was a layby near the top where I pulled in and let it cool, no flashing lights, guage went just short of top.
Removed radiator back at the garage to find a load of debris in the bottom.
Second hand radiator fitted.
Aux water pump not working, found wrong sender unit fitted, replace with correct unit from VW.
Cam timing checked, okay.
Pump timing checked, .88mm lift at TDC, according to my AutoData CD that was okay.
I notice that there is 4 different types of injection pump fitted to the AAZ, this one has a aneroid, and it's connected, although no smoke screw.
It has a metal pipe coming from the pump end of the injection pipe going to what looks like a stop solenoid then the pipe goes down to the advance part of the pump, should this be energised or left alone?
When started the engine runs fine, warms up quickly, which surprised me for me Diesel and if left idling the guage will stay at 1/2 however when the van is driven the guage climbs again, not as bad as it did but it seems to run about 3/4's
Im 99% sure the cooling system is now good, the rad is fully warm as are the heaters.
No intercooler fitted yet.
No oil cooler fitted yet, the engine is stock so I didn't see the point.
Van runs great, quite quick, well if you've driven a 1.6TD Vanagon you'll know why!
Anyone any ideas whay it should run warm?
Think im going to connect an aux coolant temp guage just to make sure the instruments aren't telling lies!
I've got a feeling that it's just the guage not giving an accurate reading, oh, and the header tank cap was duff, this has been replaced with new.

[srivett]

If it is smoking it will be heating up quickly.  A common cause is a plugged air filter or a big hill.  One other thought is with regards to the size of the rad you're using.  Is it as big as one found in an AAZ car?  Is the fan kicking in?  It should kick in roughly at a high 3/4 and take the temp down to a low 3/4 gauge indication.

Steve

[jtanguay]

I'd add the oil cooler for sure, and maybe do a rad flush?  Do you run it in boost for extended periods of time?  My car only heats up on the highway while the turbo is constantly going.

[Otis2]

I have an AAZ in a full Westy Vanagon.  The engine has the standard VW car (kinda wimpy) oil/water exchanger just above the oil filter.  At least, this is the standard oil cooler on North American AAZ engines.  I do not have an auxiliary water pump - I suspect you are talking about an electric pump.  Maybe this was available on the Euro T3 1.6TD, but it was never seen here.  No factory T3 turbodiesels ever exported over here.  You gotta roll your own.

My van had a new radiator installed just before I bought it, and this seems to be doing yeoman service.  When I start from idle and run it hard up a long hill, my oil temperature rockets in the blink of an eye (from 190 to 230 F) and my oil pressure falls, but the water temperature stays rock steady.  So if anything, I'm interested in tying the oil temperature more closely to the water temperature, since it's the water temperature that stays cooler than the oil.

I think your problem is in the radiator.  The second-hand one you fitted is probably nearly as plugged as the first.  They are expensive, but a new T3 radiator may be exactly what you need.

Then once that's sorted, you can address the inadequate oil cooling (which you will only notice with aftermarket gauges and big hills).  But these are separate problems, I think, and unrelated.

Wait for the "smart kids" here at GTD to comment before buying the rad, though.  I'm not yet in that category.

[VWRacer]

I'm with Otis on this one. I can't tell you how many times I've seen a new or properly rebuilt radiator cure a mysterious overheating issue.

What would cause a AAZ to run really hot under load? Took on long test drive once done, took it up a reasonably long drag and it got kinda hot, there was a layby near the top where I pulled in and let it cool, no flashing lights, guage went just short of top.

And of course, confirm the rad fan(s) are coming on! If your temps spike after pulling off the road, I'd suspect the fans not coming on.

[QuickTD]

I have heard of several cases of water pump impellers coming loose on the shaft. This usually causes overheating at high speed but no problems at idle and low speeds. Might be worth a look.

 The extra stop solenoid looking deveice on the side of the pump is part of the load dependant timing system. On the AAZ jetta and golf the solenoid was energized (and load dependant timing disabled) at ~2800rpm by an engine speed controlled switch located in the glow time control module. Basically, the system retards the injection timing at low engine speeds to reduce the formation of NOX. For best performance and fuel economy I would energize the solenoid at all times.

[dieselweasel]

As you already stated, before getting carried away verfiy the accuracy of the gauge.  An infrared heat gun works well for this or a thermometer in the expansion tank would work.

[Baxter]

Just to follow up.
Got it sorted in the end.
Culmination of problems.
Rad was bunged up with sludge.
The wrong sender was fitted for the aux water pump.
Header tank cap wouldn't hold pressure.
Fitted a new fan switch as a matter of course.
The temp guage was a liar! I swapped the snder but the van runs at 3/4, and did with the old engine.
Cheers for the input guys, Im a mechanic but not affraid to ask for some poiters, sometimes you can't see the wood for the trees, my main worry was that I had wired the solenoid up on the pump constantly when it shouldn't have been.
The customer is going to run the vehicle around for a while so we can iron out the niggles then Im on the lookout for a oil cooler, once thats on I'll have a play with an intercooler, the boost pressure and up the fuelling.
Again, thanks.